Interpretive Summary: Saponins are naturally occurring compounds found in roots, shoots, seeds, and flowers of many plant species, including chickpeas, navy and kidney beans, soybeans, alfalfa, cereals, peanuts, and asparagus. Saponins can be extracted and used in the food industry as foaming agents in soft drinks, baked goods, candies, and dairy desserts. Combination spray treatments of water washes followed by an antimicrobial rinse are currently used by the meat industry to reduce both bacterial and visible contamination on meat animal carcasses. This study determined if the foaming property of saponins could be combined with water washing for removing bacteria from beef surfaces. For both experiments, beef tissues were inoculated with cow feces and subjected to different spray washing treatments. When saponin was combined with water or vinegar, more aerobic bacteria were removed from the beef tissue than were removed by single washes with saponin, water, or vinegar. However, when saponin was combined with water or vinegar, bacteria were not removed from beef surfaces any better than when spray washes of water with water or water with vinegar were applied. Based on these findings, combination washes incorporating saponin were no more effective than combination washes of water with water or water with vinegar for removing bacterial contamination from beef surfaces.

Technical Abstract:
Saponins are naturally occurring compounds known as triterpenoide glycosides and are found in a variety of plant species. Saponins are approved for use in the food industry as foaming agents. When combined with the current practice of water or organic acid spray treatments, the foaming property of these compounds may provide an added benefit in carcass decontamination. In the first experiment of this study, lean beef carcass surfaces were experimentally inoculated with a fecal slurry containing antibiotic resistant Escherichia coli O157:H7 and Salmonella typhimurium. Spray washing treatments with saponin-water (SW) or saponin-acid (SA) were more effective for reducing aerobic bacteria than saponin (S), water (W), or 2 per cent acetic acid (AA) washes alone. However, SW and SA treatments were equally or not as effective as AA for reducing populations of E. coli O157:H7 or S. typhimurium. In the second experiment, experimentally inoculated beef surfaces were subjected to spray treatments with water-water (WW), water-acid (WA), SW, or SA. When examined against all populations, SW or SA were as effective treatments as WW or WA for reducing aerobic bacteria, E. coli O157:H7, and S. typhimurium from beef surfaces. Under the conditions described, reductions associated with combination spray washes may be attributed to the physical removal of bacteria during the spraying process, and not to any specific action of saponin.